What are narcotics' effects on the body?

Quick Answer
Narcotic is another word for opioid drugs, or opiates, which have been used throughout human history to relieve pain. Historically, narcotics were naturally derived from the poppy plant. The narcotics prescribed today may be natural or synthetic. These drugs include morphine, heroin, codeine, opium, hydrocodone, oxycodone, meperidine, and methadone.
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Addiction to Narcotics

Substance use is a choice, but over time the use of substances can develop into dependency. The overuse, or abuse, of substances brings lasting physiological changes to the brain that lead to psychological and behavioral changes. With the abuse of narcotics, the damage to the brain is profound.

Addiction is a brain disorder. Narcotics disrupt the biochemical processes of the brain, eventually leading to addiction. To understand the damage of narcotics abuse requires an understanding of why narcotics are used and how they alter the brain.

Because narcotics (opioids) produce a euphoric state of relaxation, even sleep, they serve a medical purpose for controlling pain. Narcotics affect the mu (µ) opioid receptors in the brain, also known as the painkilling parts of the brain, or the reward pathway. When abused, narcotics block endorphins, the brain’s natural pain-control chemical. A person with narcotics addiction experiences profound disruptions to normal brain activity and therefore feels a powerful need for the drug in order to maintain normal functioning and avoid withdrawal symptoms. Increasingly, the addict needs higher doses to feel the same effects.

In his book Helping the Addict You Love, Laurence W. Westreich warns the friends and relatives of addicts about the damage to the brain that substance abuse causes and how it leads to the impairment of judgment and common sense. Love and logic are not enough to convince an addict to stop using the substance. Much more occurs in the body physiologically with addiction that can hamper the addict’s decision-making abilities and impulse control.

According to Westreich, several models explain why a person becomes addicted to a substance. Based in neuroscience, the learning theory model suggests that addiction evolves from the reward mechanism in the brain. The high is the reward, and the brain adjusts to receive more of the reward. The self-medication hypothesis suggests that people abuse substances as a way of coping with traumatic events and stress in life.

The biopsychosocial model assumes that addiction is driven by a combination of psychological and social factors and, therefore, must be treated at the same time other underlying factors are treated. The moral model assumes a fault in the addict’s moral character as the fundamental cause for the development of the addiction. Conversely, the disease model considers addiction a disease or a medical condition that must be treated medically, and not as a defect in the addict’s moral character.

In their book Freedom from Addiction, David Simon and Deepak Chopra summarize the impact of narcotic drugs on the body this way: “Opiate-derived chemicals directly activate the pleasure receptors of the brain, bypassing all usual methods to achieve comfort.” They continue, “When the opiates are metabolized, the body is left without intrinsic or extrinsic pain relievers.” Therefore, the short-term impact on the body is intense pleasure and pain relief, while the long-term impact is the inability of the brain to regulate pleasure and pain in the body normally.

Narcotics Abuse Versus Dependency

In Addiction: Why Can’t They Just Stop?, researchers John Hoffman and Susan Froemke define substance abuse and substance dependence. Accordingly, abuse is “a pattern of substance use that causes someone to experience harmful consequences,” which includes failing to meet key responsibilities; engaging in reckless activity; and refusing to resist the substance despite recurrent interpersonal, occupational, and financial problems brought on by drug use. Dependence is a physical addiction to a substance resulting in physiological and behavioral changes to the user. Physiologically the dependent person needs increasingly higher doses of the substance to achieve a high. He or she then experiences intense withdrawal symptoms when deprived of the substance. Behaviorally the person is obsessed with acquiring the next dose, prioritizing the substance over all relationships and obligations, including care for his or her own health.

Some people can become addicted to narcotics without necessarily abusing narcotics. Rather, they may become dependent on narcotics from using them to manage chronic physical pain over an extended period of time. Even when narcotics are prescribed by a doctor, patients must be aware of the drugs’ potential for dependency and addiction. Although many of these drugs are obtained through prescriptions, dependence or abuse of narcotics often falls into the category of nonmedical use. According to the Substance Abuse and Mental Health Services Administration, in 2013 53 percent of users had access to the drugs through a friend of family member and 21.2 percent of users obtained them through a prescription.

A continuum exists among opioid abuse, opioid dependence, and addiction. Signs of abuse include the user’s inability to fulfill normal responsibilities and the prevalence of interpersonal problems. Dependence is characterized by the consumption of larger and more frequent doses of the narcotic over a span of time, an increased tolerance of the effects (the high) of the narcotic, and a clear demonstration that the user is obsessed with acquiring the narcotic regardless of cost to his or her own health and personal relationships. Addiction is the state in which the craving for the narcotic becomes so compulsive and overpowering that the addicted person’s behavior becomes grossly self-destructive.

Short-Term Effects

Opiate narcotics like heroin, morphine, and prescription painkillers (such as oxycodone and Vicodin) will produce a surge of euphoria and drowsiness. The short-term effects of narcotics include relaxation, sleepiness, pain relief, an inability to concentrate, apathy, flushing of the face and neck, constipation, and nausea and vomiting.

Opiates also can slow systems in the body, such as the nervous, respiratory, and digestive systems. Physical dependence can become severe and can gravely affect the body’s normal nervous, respiratory, and digestive functions. Heroin tricks the brain’s neurotransmitters by activating abnormal messaging. In effect, the reward circuit of the brain is overstimulated.

Long-Term Effects

Long-term abuse causes the brain to adapt to the drug-induced surges of dopamine, thereby producing less of its own dopamine naturally. The most significant long-term effect of narcotics abuse is this reduction of dopamine and dopamine receptors in the brain. The brain then cannot stimulate the reward circuit on its own. The neurotransmitter glutamate is permanently altered, and the brain develops a drive to achieve messaging to the reward center through narcotics. This desire trumps all other decisions and judgments.

Addiction is the underlying long-term effect on the body. The body craves the substance biologically just like it does food. “The addict’s need for his or her substance of choice is like a starving person’s primal need for food,” Westreich explains. “Drugs and alcohol literally ‘hijack’ the brain, physically and emotionally driving the addict to find, use, and keep using whatever drug he or she has chosen.” Once addicted, withdrawal is a necessary challenge to overcome when first embarking on the journey of recovery. In withdrawal from opiates, whether street heroin or prescription pain pills, the addict will experience extreme restlessness, severe pain in the muscles and bones, diarrhea, vomiting, and cold sweats. Heroin and morphine use can also cause permanent damage to the body through bacterial infections of the blood, heart valves, liver, or kidneys. Heroin, morphine, and prescription painkillers also can cause serious damage to the lungs if inhaled or snorted.


Hoffman, John, and Susan Froemke, eds. Addiction: Why Can’t They Just Stop? New York: HBO, 2007.

Lawford, Christopher Kennedy. Moments of Clarity. New York: Morrow, 2009.

"Results from the 2013 National Survey on Drug Use and Health: Summary of National Findings." SAMHSA. SAMHSA, Sept. 2014. Web. 30 Oct. 2015.

Simon, David, and Deepak Chopra. Freedom from Addiction. Deerfield Beach, FL: Health Communications, 2007.

Westreich, Laurence M. Helping the Addict You Love. New York: Simon & Schuster, 2007.

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